1. Field of the Invention
Aspects of the present invention relate to a mini base station connectable with the Internet being installed separately from a cellular base station.
2. Description of the Related Art
Generally, terminals including a cellular phone, a notebook PC, a personal digital assistant (PDA), and the like communicate with a cellular base station. The cellular base station has a cell coverage, and communicates with the terminals located in the cell coverage.
The size of the cell coverage of the cellular base station is limited. A shadow area in which the cellular base station and the terminals cannot communicate with each other may be generated due to barriers, such as a building and the like.
Various schemes have been proposed in order to solve the communication barrier problem generated in the shadow area. For example, a scheme of installing a relay device or further installing another cellular base station is one proposal. Since the relay device and the other cellular base station have high installation costs and are large, installing many relay devices and cellular base stations is difficult and expensive.
Recently, research on a mini base station connectable with the Internet including a nano cell, a pico cell, and a femto cell is actively under way. The mini base station is connected with the Internet, and communicates with the terminals instead of the cellular base station, thereby solving the communication barrier problem generated in the shadow area.
When the mini base station operates in an area other than the shadow area, the terminals can receive a signal transmitted from the cellular base station and a signal transmitted from the mini base station. Accordingly, a problem due to interference can be generated. Therefore, technology of reducing the interference generated between the cellular base station and the mini base station is desired.